Many methods and techniques for manufacturing doors have been developed over time. For example, FIG. 1 shows a typical residential door 100 that is constructed from a set of interlocking perimeter boards 102, 104 and 106, internal boards 108, and panels 110 and 112. In another example, FIG. 2 shows a fire rated door 200 that is constructed from a mineral core 202 sandwiched between two medium density fiberboards 204 and 206. A perimeter channel 208 extends around the sides of the door assembly. An intumescent banding 210 is sandwiched between a first hardwood insert 212 and a second hardwood insert 214, all of which are disposed in the perimeter channel 208. Many other designs exist.
These prior art designs do not lend themselves well to fully automated manufacturing processes. Moreover, the prior art fire rated doors are expensive and require the internal mineral core. The internal core can be exposed in routed details and may reduce the strength of the door as a result of the reduced thickness of the door panels. In addition, alignment of the panels during assembly can be troublesome and require additional finishing to square the door after assembly. As a result, there is a need for a fire rated door that does not suffer from these deficiencies.